Materials clamping devices for lift trucks



Jan. 28, 1958 B. H. LOCKE MATERIALS CLAMPING DEVICES FOR LIFT TRUCKS Filed Feb. 26, 1956 United States Patent C MATERIALS CLAMPING DEVICES non LIFT TRUCKS Burton H. Locke, Framingham, Mass.

Application February 6, 1956, Serial No. 563,557

4 Claims. (Cl. 214-653) This invention relates to improvements in materials clamping devices for mounting on lift trucks generally in the place of the usual forks and to be utilized in the clamping and lifting of individual containers such as drums; cases; boxes; cartons, or the like and material arranged in the form of rolls or bales or the like.

One object of the invention is to provide a simple yet positively acting device that generally can be adapted to the lifting member of fork lift trucks and can be operated simply and positively from the truck to contact and embrace any size or shaped article substantially Within the width of the device for the purpose of lifting the same and the transporting thereof by the truck.

Another object is to provide a structure having a rigid V-shaped base extending substantially at least the width of the truck to receive and contact all shapes and sizes of articles within its limit at two points and thereby centralize the same relative to the truck and swinga'ole members pivoted at each end of the V to swing inward to abut the said articles and thereby clamp the same inwardly against the said V thereby effecting a 4-line clamping contact on the article, such a clamping to be afiorded without any preliminary sidewise adjustment of the clamping members to position the same relatively close to the article prior to being clamped, as is generally required in conventional fork lift truck clamping attachments. In other words, I conceive a construction that involves only one operative swinging motion to clamp all of said sizes and shapes of articles within a V seat and thereby afford a device that is inexpensive to construct and simple to operate and one that affords centralized clamping of the articles relative to the truck. Furthermore, swinging clamping members are substantially free from binding such as is encountered in the case of sliding members for example.

Inasmuch as the lifting mechanism of fork lift trucks is generally operated by hydraulic pressure created by a hydraulic power unit on the truck, I propose to operate my improved clamping device hydraulically from the conventional said power unit and provide a single manual control means for the same positioned at the hands of the operator of the truck. This affords a simple means of operating the simple clamping structure to be set forth.

In the accompanying drawing:

Figure 1, is a plan view of my improved clamping device as operated in the clamping of round drums or rolls of material.

Figure 2, is a side elevation of the same.

Figure 3, is a plan view of the device as it would operate to meet the clamping of square or rectangular cases or boxes.

Figure 4, is a plan view of the device as it would clamp oval shaped bales or packages.

My improved clamping device comprises a rigid base portion generally extending at least the entire width of a lift truck on which it is mounted and having upwardly extending arms or members 11 that are adapted for mounting on a rod or other conventional member ice 12 of the lifting member 1 3 of a conventional fork lift truck. The lift truck members are indicated fragmentally.

in dotted lines. The lower inner edge 14 of base ltl abuts the lower end of the said lifting member while the arm members 11 are suspending from the rod 12 of the same. This is a conventional way that forks on a lift truck are generally mounted and the intended structure of my device is such as to be mounted in place of the said lifting forks.

The outer edge portion 15 of base it is in the form of a V located generally central to the truck laterally and there is an arm 16 pivotally mounted at each outer end 17 of the v portion 15. As shown in Figure l, the normal position of the arms is as shown in full lines and the outer end portion of each arm 16 is generally arcuate inwardly to afford maximum gripping contact with large round articles such as which obviously would be relatively heavy and thus would require maximum clamping for lifting. The inner end 21 of each arm 16 is pivotally attached to the piston rod 22 of a hydraulic cylinder 23. Each hydraulic cylinder is pivotally mounted to base ll) by a stud 2-igenerally having threaded engagement in said base.

Generally a flexible pipe or hose 25 is attached to the outer end 26 of each cylinder 23 and is connected to the hydraulic power unit, not shown but generally provided on the fork lift track, by a flexible hose 27 connected substantially at the center of hose 25 so that as oil is fed through the hose to the cylinders 23 the operation of the cylinders will be equalized and simultaneous to efiect equalized clamping.

A flexible hose connection 28 to the inner end 29 of each cylinder 23 from the said power unit is made in the same manner and for the same reason as for the connection at the outer ends of the cylinders. Oil is fed under pressure to the inner end 29 of each cylinder 23 to clamp articles within the v of base 1% and to the outer end 26 of the same to release the clamping arms and return them to their normal position.

A manual operated 4-way valve, not shown, is generally provided on the truck Within reach of the operator through -which the oil flows to and from the cylinders via the said hose connections. Therefore, the operation of the cylinders and thus the clamping arms 16 can be controlled simultaneously by manual operation of the said 4-way valve.

Referring to Figure 1, when a maximum large round article 26 is clamped the arms are swung inwardly and assume the position shown by dotted lines 3%}. When a minimum small round article 31 is clamped, the arms 16 assume the position shown by dotted lines 32. Therefore, allowable maximum and minimum articles are clamped by one operation of the cylinders, or in other words, by one swinging movement of the clamping arms 16. Also, there is no preliminary side shift adjustment required to adapt the device to side shift from position to handle large articles to position to handle small articles as is encountered in clamping devices now used on lift trucks.

It will be noted that the arms 16 contact all of the articles outwardly beyond the center thereof and thereby effect a rearward pressure to centralize the articles within the V 15. This afiords a very effective clamping of the articles by effecting a 4-line contact. Obviously, the ength of the line contacts are the width of the V 15 or the arms 16 and the 4-line contact clamping of the maximum round article 20 is at 41, 42, 43 and 44. The line contacts clamping the minimum round article 31 are at 51, 52, 53 and 54.

Figure 3 shows how maximum and minimum sizes of square or rectangular cases, or the like, can be clamped by one swinging movement of the clamping arms 15. it

will be noted that rectangular articles are held securelydue to the entire inner sides of the same bearing on the sides of the V 15.

Figure 4 shows similar clamping of maximum and minimum sizes of oval shaped bales or packages of material, or the like.

Generally the V of the base 10 is 90degrees included angle in order to provide sufficient depth tothe V to permit, as shown in the drawing, all sizes and shapes of articles, or structures, that will pass between the 16 when open to be embraced and clamped securely within the V in a 4-line contact clamping arrangement by an inward swinging motion of the said arms. Also, a'90 degree V permits square or rectangular articles, or structures, to be clamped in'diagonal arrangement with the inner sides of the articles, or structures, bearing on the sides of' the V 15, as shown in Figure 3. Furthermore, a plurality of rectangular cartons or cases arranged in rectangular form, such as indicated by broken lines 33 that sub-divide the maximum square toindicate a plu rality of cases as shown in Figure 3, could'be embraced and lifted as one integral unit. One such application could be the clamping and lifting of a stack of cases off of a pallet to permit the pallet to be removed fromunder the same. In other words, the device could serve as a means to unload a stack of cases from a pallet.

Inasmuch as the arms 16 are pivotedat the outer ends of the V 15, the said arms are disposed to admit and embrace all of the said sizes and shapes of articles beyond the center of each and thereby effect a rearward clamping of the same into the V. This assures a secure clamping of the same. Furthermore, the arms 16 urge the articles against both sides of the V, as shown, and thus the articles regardless of size or shape are always clamped centrally within the V and thus central to the truck to afford even lifting thereof.

I do not wish to be confined to the exact details set forth as the same are susceptible of modification within the spirit and scope of the invention.

I claim:

1. A materials clamping device for fork lift trucks comprising a base suitable for mounting on a fork lift truck in position of the usual lifting forks thereon, said base being in the form of a substantial stationary outwardly disposed V extending horizontally along the front of said truck, a swingable arm pivoted at each outer end of said V and normally extending outwardly therefrom, said arms being disposed to swing inwardly, each toward the other, to contact any article that may be within said I and thereby effect a 4-line embracement thereof within said V, power means from said truck to operate said arms and means on said truck to control the operation of the arms.

2. A materials clamping device for use on lifting trucks was comprising a substantial horizontal disposed V-shaped base disposed centrally along the front of said truck and mounted stationary on thes-lifting -member. of. the same, a horizontally disposed swingable arm pivoted at each outer end of the V of said base and normally disposed to extend outwardly therefrom, power means to swing said arms to operatively bring the outer end portion of each toward the other for the purpose of embracing any article that may be positioned between said arms and effecting the; clamping; of the: same into the; V-shaped portion of the said base, mean tmoperate and control the said power means from the said truck.

3. A materials: clamping deviceforuseon-fork lift trucks comprisingj msnbstantial \L-shaped base disposed horizontally and being suitable for stationary mounting on the lifting member of=a lift truclc in place of the lifting forks normally mounted thereon, the V-shaped portion of said base being such as to receive and abut an article to be clamped upon movement of the truck toward said article,;a swingable armpivotallymounted at eachouter end of theV- of said base and normally disposedto extend outwardly therefrom to straddlea said article uponsaid movementof--- the truck, power means operative-fromsaid truck to swing'the said-I arms to operatively-bringtheouter end 'portion of 'eachtow-ard the other to effect a rearwardembracement of a said article between said arms andthe saidV portion-of'said base therebycffectinga 4-line centralized clampinggrip on the article,- means to operate andcontrol the said powermeans from the said truck. v

4; A materialscl'amping device for use on fork lift trucks comprising a substantial non-operative V-shaped member for horizontal mounting onand substantially central laterally to said truck on the liftingmember thereof'in place ofthe usual lifting fork s, a horizontal swinging arm member-pivotally mounted at each end-of said V member, power meansto swingsaidarms' simultaneouslyv inwardly to ernbraceand clamp; articles within said V and thereby central to said truck, manual means to operate and 'coutrol the-said power meansand therebycontrol the clamping of the said articles.

References Citeddnthe file of. this patent UNITED STATES PATENTS" 

